As the Internet access lines are growing in speed and band, a video communication service is expected to be more popular, which transfers video media including videos and speeches between terminals or between server terminals via the Internet.
The Internet is a network whose communication quality is not necessarily guaranteed. For this reason, when performing communication using speech and video media, if network bandwidth is narrow or network is congested between user terminals, the quality of the speech and video media perceived by users [QoE: (Quality of Experience)] degrades.
More specifically, quality degradation in a video is perceived as a blur, smear, mosaic-shaped distortion, and jerky effect in the video. To provide a high-quality video communication service, application or network quality design before providing the service and quality management after the start of the service are important. Hence, a simple and efficient video quality assessment technique capable of appropriately expressing video quality perceived by a viewer is necessary.
Conventionally, ITU-T (International Telecommunication Union-Telecommunication Standardization Sector) recommendation J.144 (ITU-T Recommendation J.144) defines an objective video quality assessment method. ITU-T recommendation G.1070 (ITU-T Recommendation G.1070) defines a quality estimation method to be used for quality design of a videophone. These objective assessment techniques can estimate subjective quality with the estimation error that is equivalent to the statistical uncertainty of the subjective quality under predetermined conditions.